Ad Astra Observatory

I had a few things to do before getting started tonight.
First, I replaced the brass worm gear with a steel one. This one is Art’s spare, which he used successfully for years. This replacement went a lot faster than the last. Things felt pretty smooth, I’m starting to get the hang of mount maintenance. Maybe.

Then I remounted the C9.25 and unwound all the cables. I do wonder if my cable harness is hurting my imaging rig. shrug.

It was a sad day; I retired the ST-4. It’s now sitting in baggies, waiting to be sold.

Once the sun went down, I spent some time focusing the new Guido (moved the camera from one 9×50 to another so that it’s rotateable).

The polar alignment is really close. I did a one-star alignment and was consistently dropping things into the 30′ FOV of the DSLR on the C9.25. Cool.

I spent a lot of time tweaking the guiding and PEC and stuff. It looks like I’m down in the ~5″ peak-to-peak range at the moment. That’ll work. On the other hand, I’ve convinced myself that I’m actually seeing the “mount’s” data as opposed to the “guide rig’s” data, as I’ve now tried 3 guide cameras (ST-4, webcam, Starshoot) on a variety of guide OTAs (from Pumpkin to Guido to Veronica), and I tend to see mount data with RMS in Y ~= 0.1, in X ~= 0.4. 0.1 is good enough for anyone, but is essentially the effects of seeing. My skies are steady enough to image. The 0.4 tends to be “not enough” for serious autoguiding. I get a lot of trailed stars, even with the autoguider running. Hmm.

I guess what this tells me is that Guido’s doing fine. The performance is as good as I’ve come to expect.

Now to see if I can tweak the PEC into shape.

I did several PEC training runs, but ended up with only 2 in the mount. I want to do a nice long run of guiding, maybe 14 worm cycles or so, then build a PEC curve off of that and load it. That would probably do the trick for settling out “what I can” from the mount’s idiosyncrasies.

Now the rig is out there running off 24x5min of M51. I haven’t done non-Ha imaging in awhile, so I can’t remember if I’m doing things right. The raw data looks a little blue. We’ll see if that means anything.

Lately it seems like I’m getting clear afternoons followed by a few cloudy hours near sunset, then a few clear hours, then it clouds in around midnight. That works. A few solid hours each night is a good thing.